Tanks can store fluids or liquids, including flammable fluids such as oil or gas. The fluid can corrode portions of the tank that come into contact with the fluid. External surfaces of the tank can corrode due to water or other fluids under the floor of the tank, or water that leaked into the tank through, for example, a roof seal and sank below the hydrocarbon fluid due to its higher density. Corrosive elements in the hydrocarbon fluid can also contribute to corrosion. This corrosion can eventually cause the tank to leak. However, it can be challenging to determine the integrity of the tank to prevent leaks.